ADENOSINE 5'-TRIPHOSPHATE (ATP), THE NEUROTRANSMITTER IN THE PROSTATIC PORTION OF THE LONGITUDINAL MUSCLE LAYER OF THE RAT VAS-DEFERENS

Suramin (1-100 muM) and alpha,beta-methylene adenosine 5'-triphosphate (AMPCPP, 39 muM), antagonized the motor activity induced by exogenous adenosine 5'-triphosphate (ATP) but not exogenous noradrenaline (NA) in the longitudinal musculature of prostatic (P) and epididymal (E) se gments of the rat vas deferens. Likewise, application of these drugs r educed the fast component of the nerve-stimulated contraction in respo nse to a single transmural electrical pulse in E and P. Suramin also b locked in a concentration-dependent fashion, the contractile responses to trains of 1.5, 5, 15 or 30 Hz transmural electrical pulses in P, w hile it did not affect those in E. AMPCPP obliterated responses to tra ins of 1.5, 5, and 15 Hz in P, while reducing these responses in E to a significantly lesser extent. Present results strongly support that A TP is the motor transmitter in P, while in E, ATP and NA are likely th e co-transmitters responsible for the motor tone.